The present invention relates to agricultural implements such as rippers, and more specifically to trailing leveling wheels for such an implement.
In the past, straight shank rippers have been used to fracture soil without substantial destruction of the soil surface. These rippers were designed to eliminate soil compaction without inverting soil layers or significantly disturbing the surface residue. Farmers use these rippers because they want to have the root growth and water movement benefits from ripping the soil without being penalized with a loose, uneven and easily evaporated surface profile in the spring. Ripper points designed to reduce surface profile variability are shown, for example, in U.S. Pat. Nos. 5,437,337 and 5,540,288. The points leave the surface profile substantially undisturbed by not displacing fractured soil. Because the points are designed to leave surface profile generally unchanged, soil fracturing in the compaction layer is at a minimum. With little lateral movement of soil, the fracture zone is only a slot, and water intake and retention properties are compromised. An optimum seedbed for promoting good root growth is also compromised by the limited soil fracture characteristics of points that have little fractured soil displacement.
Straight toolbar, straight shank rippers with variable force closing/firming wheels have been used to fracture soil while maintaining a generally level soil surface. An example of such wheel structure is shown in U.S. Pat. No. 6,012,534. Such rippers typically utilize straight 0.75 inch thick ripper shanks, low soil disturbance points, and the closing/firming wheels. The shanks and points lift the entire soil profile without displacing a considerable amount of soil from the ripper slot. The wheels, which run closely adjacent the sides of the shank, contain the soil at a point where it begins to erupt due to the action of the point. The wheels push the loose soil back into the ripper channel thus leveling and sealing the ground for future crops. The wheels can also be used to shatter soil clods displaced by the ripper shank.
The closing/firming wheels firm soil that is still flowing over and around the ripper shank, and therefore the wheels are not able to firm the final soil profile. Therefore, a level profile is not achieved in some soil conditions. The relatively compact, closely coupled wheel arrangement has a very limited vertical movement range and hinders the ability to change force settings for a particular ripping depth. The downpressure mechanism has to be adjusted according to the selected ripping depth, and when the operator changes the ripping depth during operation the wheel downpressure will change substantially unless a time-consuming adjustment of individual downpressure mechanisms is made. The closely coupled wheels also hinder trash flow and promote residue plugging between the shank and the closing wheel arms. The limited working range of the wheels often results in shear bolt breakage when large surface obstructions are encountered. The closing wheels do not contact the ground until the ripper points penetrate the ground a substantial distance, and soil surface profile in the turn-row areas are adversely affected. The wheel mounting arrangement provides little or no angular adjustment of the wheels to vary the amount of soil pulled over the ripper slot.
It is therefore an object of the present invention to provide an improved leveling wheel assembly for a ripper. It is a further object to provide such an assembly which overcomes most or all of the above problems.
It is another object of the present invention to provide an improved leveling wheel assembly for a ripper which leaves a satisfactory soil surface profile in a variety of soil conditions. It is a further object to provide such an assembly which firms the final soil profile.
It is still another object of the present invention to provide an improved leveling wheel assembly for a ripper or similar agricultural implement which has improved downpressure characteristics when compared to at least most previously available leveling wheels. It is another object to provide such an assembly which obviates time-consuming downpressure adjustments when ripper depth is changed. It is still another object to provide such a mechanism which maintains the wheels a relatively constant distance behind the ripper shank as the ripper depth is changed.
It is yet a further object of the present invention to provide an improved leveling wheel assembly for a ripper having improved residue flow and reduced residue plugging problems. It is yet a further object to provide such an assembly which allows the soil and residue to settle prior to being firmed to provide a more level surface.
It is another object of the present invention to provide an improved leveling wheel assembly for a ripper wherein downpressure adjustments can be made quickly and easily for varying soil conditions. It is yet another object to provide such a mechanism wherein closing wheel spacing and angle relative to the direction of travel are easily adjustable and wherein the angle is adjustable over a larger range compared to at least most previously available leveling wheel assemblies to accommodate a wider variety of soil and trash conditions. It is yet another object to provide such an assembly with a simple downpressure adjustment.
It is yet another object of the present invention to provide an improved leveling wheel assembly for a deep tillage implement having a substantially larger vertical operating range compared to at least most previously available leveling wheel assemblies. It is still another object to provide such an assembly which contacts and levels the soil over a substantial range of vertical adjustment of the deep tillage implement and improves leveling in the turn-row areas where the implement is being lowered into or raised from the ground. It is a further object to provide such an assembly which reduces or eliminates the problem of shear pin breakage when large obstacles in the surface are encountered.
A leveling wheel assembly for a deep tillage tool such as a ripper includes a wheel support bracket fixed to the upper end of the ripper shank and extending rearwardly therefrom to an aft end located a substantial distance behind the rear edge of the shank. A wheel support arm pivotally connected to the aft end extends downwardly and rearwardly and is connected to wheel support structure rotatably mounting a pair of leveling wheels. An adjustable downpressure spring is supported between the aft end and the lower end of the wheel support arm and works through a three-bar linkage arrangement providing an effective moment arm that decreases as the spring compresses to provide a generally constant downpressure as the wheels move vertically with respect to the shank over a substantial range of ripper working depths. The wheel support structure includes slots for adjusting the spacing of the leveling wheels and the angle of the wheels relative to the forward direction and the horizontal.
The wheels level the soil several feet behind the point to allow the soil and trash to settle before contact so a more uniform surface is provided. The spacing between the wheels and ripper point also decreases the likelihood of residue hairpinning between the ripper shank and the closing wheels. The leveling wheel support arrangement provides closing wheel vertical travel of nearly 1.5 feet, and an operator can rip from 5.5 to 16 inches deep without having to make any closing wheel adjustments. They can also run over field obstructions nearly 23 inches above the ripper point without having to replace a shear bolt. The large vertical travel range of the wheels also allows for more level soil profiles on the turn-rows because the closing wheels contact the ground with less than half a foot of soil penetration.
The wheel angle adjustment provision allows the operator to vary closing wheel spacing several inches depending on soil blowout. Closing wheel angle relative to the direction of travel is also adjustable up to approximately 15 degrees to pull more or less soil over the ripper slot depending on soil conditions.
These and other objects, features and advantages of the present invention will become apparent to one skilled in the art upon reading the following detailed description in view of the drawings.